How controller works?
 

Good morning, I'm a car-motorcycle-videogame enthusiast. I like RC car but I never bought one.
I have a curiosity, and maybe in this forum I can find the answer.
Just keep calm because I really am not an expert of RC cars, so if I ask nonsense questions, it is not my intention to offend.

I play with simulation games (like assetto corsa, dirt rally...), using racing wheel, but sometimes I like to use an xbox gamepad.
If the gamepad worked like a wheel (direct input), 5mm of movement of the stick corresponds to 400° rotation of the steering wheel. The car will be undriveable, I try.
The only way to use it is to add filter (to smooth the input), velocity sensitivity (to reduce the max wheel angle with the speed, so, for example, 5mm of stick movement at 20 km/h is 400°, at 100 km/h is 150°) and other parameters.
Usually in game these parameters are default and hidden, in simulation games you can modify and remove it.

Now, my question: RC cars are real life cars... smaller, but obey to the physic laws like the bigger one. And they are controlled using a radio controller similar to a gamepad.
So, in the radio controller, there are parameters like the one in racing games? or the input is direct at each speed?
If the answer is the second, how is it possible to control the car? maybe the car is setted to slide more and so the input is smoothed by the car, and not by the controller?
Thanks

The answer depends a lot on the radio in question, in my answer I'll talk about computerised radios that we tend to use for racing. The radios that come with 'ready-to-run' RC cars often don't have all of these adjustments, but usually still some basics. For cars, the radios used are usually a wheel and trigger design rather than a gamepad or 'stick' style radio. Although in the minority there are pros, amateurs and in-between who use stick radios for cars.

First, we adjust 'sub-trim' or 'trim' settings to centre the steering. This is because every vehicle has different requirements for installing the servo, and even in the same vehicle a different servo may have a slightly different alignment of the output shaft.

Next, we set endpoints to match the physical limits of where the steering can travel. This is often a different value at each side of the steering. This sets the total range of movement of the steering.

The next adjustment is called 'dual rate'. This sets the percentage of the total travel of the steering. So rather than setting a steering range in degrees, we set the steering based on percentage of total travel. Often the vehicle is easier to drive with less than 100% steering range, so this is reduced down to a drivable setting.

There are many other settings that can be adjusted including 'exponential' which can give the sticks more or less sensitivity along their travel, adjustments for how quickly the steering movement will happen, adjustments to delay in response from radio input to steering output etc.

While it is possible to have the steering become less sensitive at higher speeds using telemetry, this is not common. Usually the travel of the steering is the same at low or high speed. However, there are many other physical adjustments to the vehicle's suspension and geometry that will effect the steering.The car can be physically set to slide more as you say, or may understeer under full power but then be more responsive off throttle. There are often more things to adjust on these cars than their full scale counterparts!

I have never had a problem using a gamepad to play an XBOX game. :confused: Frankly my times are normally worse using a wheel in Forza.

to add onto what mushroomed discussed, the fundamental feature for traditional RC controllers is "Variable Rate" controls... this is the ability to control throttle and steering proportionally where a gamepad will go instantly from 0% to 100% throttle and cause the car to spin out of control. An RC controller will gently increase the throttle proportionally and you squeeze the trigger which doubles as traction control during acceleration, same method for steering input as well.


The closest I've see is this joystick style module here though it has been discontinued because it wasn't popular:

https://www.kopropo.co.jp/en/products/view/10502

There's plenty of dual analog stick gamepads out there, so this controller behavior is pretty much a thing of the past.

Since ps3 "gas" and "brake" are fully proportional on r2 and l2 trigger style "buttons"
when thinking about it Im pretty sure I would be better at driving with rc style pistol radio then with usual console controllers